1. Field of the Invention
The present invention relates generally to the preparation of electrical components formed of certain lanthanide chalcogenide compounds and, in particular, to the preparation of electrical components formed of silver and copper lanthanide chalcogenides.
2. Description of the Prior Art
The use of inorganic materials such as silicon and gallium arsenide in the formation of electronic circuits and microcircuits (e.g. thermal on off switch) for controlling the flow of current at varying temperatures is well known.
U.S. Pat. No. 2,814,004 to Goodman discloses an electrically semiconductive object comprising a body of semiconductive material which includes a chemical compound having a formula MNX.sub.2 where M represents one of the elements copper and silver, N represents one of the elements aluminum, gallium, indium and thallium, and X represents one of the elements sulphur, selenium and tellurium. Goodman also discloses a method of producing an electrically semiconductive object by melting together in an inert atmosphere at high temperatures quantities of a first group of elements copper and silver, at least one of a second group of elements aluminum, gallium, indium and thallium and at least one of a third group of elements sulphur, selenium and tellurium in atomic proportions determined by the formula MNX.sub.2 and then cooling the melt to form the semiconductor object upon solidification. The electrical components and the method of preparing the same as disclosed by Goodman are limited to semiconductors, that is transistor type devices such as a crystal diode.
Japanese Patent No. 60-191,006 discloses a method for preparing lanthanide sulfides, selenides and tellurides by heating a mixture of a lanthanide alkoxide with the appropriate hydrogen sulfide, hydrogen selenide or hydrogen telluride. The resultant metal sulphide, selenide and telluride can be used to prepare, for example, optical disc. The disclosure of Japanese Patent No. 60-191,006, however, does not suggest that the resultant metal sulphide, selenide and telluride have any electrical properties and thus are useful as semiconductors such as diodes or other electronic devices.
U.S. Pat. No. 4,061,505 to Hampl discloses certain N-type thermoelectric compositions based on a rare-earth metal selected from gadolium and erbium and a chalcogen selected from selenium and tellurium. The thermoelectric compositions of U.S. Pat. No. 4,061,505 may be used as thermoelectric legs in thermoelectric generators.
While the prior art discloses a very limited use of selenium or tellurium in the preparation of compositions which exhibit semiconductor characteristics, a detailed disclosure and analysis of the many useful electrical components which may be formed from certain lanthanide chalcogenide compounds is not found in the prior art.